A well system (e.g., an oil or gas well for extracting fluid or gas from a subterranean formation) can include various well tools in a wellbore. For example, the well tools can include a mud motor and a geo-pilot tool. It can be desirable to wirelessly communicate data between the well tools. The power transmission efficiency of a wireless communication, however, can depend on a variety of factors. For example, the power transmission efficiency can depend on the conductivity of fluid in the wellbore and the conductivity of the subterranean formation. It may not be practical or feasible, however, to vary the characteristics of the fluid or the subterranean formation to improve the power transmission efficiency. As another example, the power transmission efficiency can depend on the design of the antennas used to transmit and receive the wireless communications. An antenna design that maximizes the power transmission efficiency in one downhole environment, however, may minimize the power transmission efficiency in another downhole environment. It can be challenging to wirelessly communicate between well tools efficiently.